1. Technical Field
The present invention relates to an airbag for a blood pressure measuring device, and more particularly to an airbag for a blood pressure measuring device used for fixing a cuff (pressure band) to a part to be measured.
The present invention also relates to a method of manufacturing the above-mentioned airbag for a blood pressure measuring device.
2. Related Art
Conventionally, as an airbag used for fixing a cuff (pressure band) to a part to be measured in a blood pressure measuring device, as disclosed in Patent Document 1 (JP 2005-230175 A), for example, there has been known a curler pressing airbag in which a living body pressing airbag is disposed outside a curler, and the living body pressing airbag is inflated such that an outer peripheral surface of the curler is pressed inward thus decreasing a diameter of the curler, whereby the living body pressing airbag is pressed to a part of a human body by way of the curler.
Hereinafter, this type of airbag is briefly described with reference to FIG. 6 and FIG. 7.
FIG. 6 is a schematic view showing an in-use state of a blood pressure measuring device 101 of an upper arm automatic wrapping type. In the blood pressure measuring device 101, an airbag 108 is inflated by supplying air into the airbag 108. The airbag 108 is maintained in a pressure-applied state so that a diameter of a curler 110 is decreased, whereby a cuff 113 is fixed to an upper arm portion 100 by the curler 110.
FIG. 7 is a view showing a state where the airbag 108 is inflated, and the upper arm portion 100 inserted into the blood pressure measuring device 101 is fixed by the airbag 108 and the curler 110. As shown in FIG. 7, constricted portions 104 which prevent the inflation of the airbag 108 are disposed along the circumferential direction of the airbag 108. The airbag 108 is inflated in such a manner that six projecting portions which project inward are formed by pressurized air, and peak portions of six projecting portions uniformly press the curler 110. As a result, a diameter of the pressed curler 110 is decreased so that the cuff 113 is fixed to the upper arm portion 100.
As shown in the figure, the constricted portions 104 are formed in the airbag 108 at equal intervals in the circumferential direction such that a plurality of projecting portions are formed due to the inflow of pressurized air into the airbag 108. The constricted portions 104 are formed by welding portions of opposed inner walls of the airbag 108 to each other.
As a technique related to welding, Patent Document 2 (JP 61-100228 A) discloses a cuff for measuring a blood pressure provided with a bag portion formed by welding peripheral edge portions of a pair of flexible resin sheets to each other. In Patent Document 2 (JP 61-100228 A), the bag portion is formed by welding a pair of flexible resin sheets to each other using high-frequency welding in a state where the other resin sheets are interposed between the flexible resin sheets. With such a configuration, the decrease in thickness of the flexible resin sheet caused by the welding step is compensated for by thicknesses of other interposed resin sheets so that the decrease in strength of a welded portion can be suppressed.